Proposals to heat materials in ovens by heated air are known. For example, Langhammer U.S. Pat. No. 4,155,294 granted May 22, 1979, shows an air heated oven having a cylindrical space extending from the front of the oven rearwardly. Hot air is introduced into this cylindrical space somewhat tangentially near the bottom and withdrawn at the top for recirculation. The material to be heated is placed in a foraminous container within the cylindrical space and hot air is blown by a circulating fan past it from the tangential inlet below it to and out of the top outlet. The formaminous container is movable into and out of the cylindrical space by means of a handle. When the foraminous container is in place in the oven, the front opening into the cylindrical space in closed to prevent loss of hot air during operation. The material is stationary during heating by the circulating hot air and the air flows over it as an onflowing steam. Other ovens which use convection and/or microwave heat disclose air circulating means, e.g., Larson U.S. Pat. No. 4,332,992 granted June 1, 1982; Shin U.S. Pat. No. 4,369,347 granted Jan. 18, 1983; and Smith U.S. Pat. No. 4,409,453 granted Oct. 11, 1983, all disclose means for circulating air through the chamber where the materials to be heated by convection and/or microwaves are placed for heating.